I worked for a top ten academic research library, and even with budgets in the millions to low ten of millions, there were still plenty of journals we were not

I worked for a top ten academic research library, and even with budgets in the millions to low ten of millions, there were still plenty of journals we were not buying. Other than the big bundles, often times it was pressure from professors that would force a specific big-ticket journal to be acquired. If sci-hub.io stops those professors from making requests to the library, then there won't be as much pressure to pick up every last journal.